Diff Ratio ID
 

I have a '72 K/5 parts truck. I want to cannibalize the rear axle for a replacement on my '71 Jimmy 4x4. I pulled the differential cover and read off the following numbers:
326663
N
GM 34
3817779
14:43
GM 09752
015 [hand stamped]
This is an open diff 12 bolt.
We turned the tire about 3 times for one turn of the ring gear.
I'm guessing 3.07:1,
I was hoping for a 3.73:1 for a direct replacement. I might get by with the 3.07 temporarily while I rebuild the 3.73 Posi, if I disconnect the front prop shaft so I [or someone else who is not familiar with the swap] don't accidently shift into 4WD and tear up the driveline and/or transfer case.

Re: Diff Ratio ID
 

43 divided by 14 is 3.07.

Re: Diff Ratio ID
 

Well maybe I'll swap out the axle for something that works. I did the math after I posted. As I recall. I once read 41.11 on a ring gear and assumed it meant it was a 4.11 rear. But a real machanic said I had to divide. So 11 into 41 is 3.7272727 = 3.73, then 14 into 43 = 3.0714286 :. 3.07.
I have a downed '67 K/10 Suburban with a 12-bolt 3.73 and auburn posi that I had rebuilt in the mid '90s. May be the best candidate. Putting a 3.07 rear on a 4x4 with a 3.73 D44 front is asking for trouble.

Re: Diff Ratio ID
 

yeah, that would make for a rough ride!